The inquest has opened into the death of an innocent Brazilian man in the wake of the 2005 suicide bombings in London, amid high security and protests by supporters.
Jean Charles de Menezes was shot seven times in the head at close range in a London underground train by police on 22 July 2005.
He was mistaken for a suicide bomber following the 7 July bombings which killed 56 and the bungled similar attacks on 21 July.
The two police firearms officers who shot the 27-year-old electrician will give evidence for the first time at the inquest, expected to last three months, although their identities are expected to be concealed.
The inquest will also be first time for the family to question those involved in his death.
Cousins of Mr de Menezes made no comment as they arrived for the inquest.
Alex Pereira, Alessandro Pereira and Patricia da Silva Armani have campaigned since the shooting.
Scotland Yard was heavily criticised in a report in August 2007 on the mistaken killing.
